Memorandum presenting a theoretical analysis of the supersonic flow about two-dimensional and three-dimensional axially symmetric models restricted by theoretical walls capable of removing the nose shock. Results regarding the supersonic-tunnel interference due to nonreflecting walls and supersonic-tunnel interference due to porous walls are provided.

This progress report discusses progress on oxidation-reduction studies, including polarography, as well as the Uranium-complex formation including electrical transport and spectro-photometric work. This report covers the work done in the period of February of 1945.

Memorandum presenting the Bell X-5 research airplane tested at 58.7 degrees sweepback during the program to determine the characteristics of a variable-sweep fighter airplane at transonic speeds. This paper includes the stability and control characteristics in the stable lift range up to Mach numbers near 1.0 at an altitude of 40,000 feet and to slightly lower Mach numbers at altitudes of 25,000 feet and 15,000 feet. Results regarding general comments, static stability and control characteristics, and longitudinal dynamic stability are provided.

An investigation was conducted on a 35 deg swept-wing fighter airplane to determine the effects of several blunt-trailing-edge modifications to the wing and tail on the high-speed stability and control characteristics and tracking performance. The results indicated significant improvement in the pitch-up characteristics for the blunt-aileron configuration at Mach numbers around 0.90. As a result of increased effectiveness of the blunt-trailing-edge aileron, the roll-off, customarily experienced with the unmodified airplane in wings-level flight between Mach numbers of about 0.9 and 1.0 was eliminated, The results also indicated that the increased effectiveness of the blunt aileron more than offset the large associated aileron hinge moment, resulting in significant improvement in the rolling performance at Mach numbers between 0.85 and 1.0. It appeared from these results that the tracking performance with the blunt-aileron configuration in the pitch-up and buffeting flight region at high Mach numbers was considerably improved over that of the unmodified airplane; however, the tracking errors of 8 to 15 mils were definitely unsatisfactory. A drag increment of about O.OOl5 due to the blunt ailerons was noted at Mach numbers to about 0.85. The drag increment was 0 at Mach numbers above 0.90.

Report presenting an investigation of hot-pressed molbdenum disilicide bodies produced by industrial processes at a temperature of 2950 degrees and a pressure of 3000 pounds per square inch. Results regarding the short-time tensile strength, stress-rupture data, compression strength, air-corrosion resistance, hardness, coefficient of linear thermal expansion, thermal conductivity, and density are provided.

Memorandum presenting an investigation conducted to measure and compare the total-pressure recovery and distortion characteristics at the compressor face of two single-place fighter-type airplanes with similar two-spool turbojet engines, but with dissimilar inlets. The total-pressure recovery was relatively independent of angle of attack and mass-flow ratio for both airplanes except for a significant decrease in pressure recovery with angle of attack for airplane B at the highest Mach numbers tested.

Report presenting tests of an NACA 4-(5)(08)-03 two-blade propeller in the 8-foot high-speed tunnel for blade angles of 45 and 60 degrees extending the Mach number range from that of previous tests of the propeller up to Mach number 0.913. When the forward speed was increased from a low value to a forward Mach number of 0.90, the loss in peak efficiency was found to be not more than 47 percent.

Report presenting data gathered on a lateral-trim change or wing dropping that involves a rapid change of lateral trim with Mach number, which has occurred on several rocket-powered models used in roll investigations at transonic speeds. The data in this report demonstrates that straight wings with airfoil sections 9 percent thick or greater are susceptible to wing dropping between Mach numbers of 0.9 and 1.0. Results for straight, sweptback, and delta wings are provided.

Report presenting wind-tunnel testing to determine the low-speed lift, drag, and pitching-moment characteristics of a 40 degree sweptback wing with high-lift and stall-control flaps and a fuselage with a fineness ratio of 10.2 to 1. Low, medium, and high-wing-fuselage combinations were tested at high Reynolds numbers. Results regarding the high-lift and stall-control flaps and wing-fuselage combinations are provided.

From Summary: "Theoretical performance data including nozzle-exit temperature, specific impulse, volume specific impulse and composition, temperature, and mean molecular weight of reaction products based on frozen equilibrium and isentropic expansion are presented for 13 propellant combinations at reaction pressure of 300 pounds per square inch absolute and expansion ratio of 20.4. On basis of maximum specific impulse alone, five fuels had the following order for any given oxidant: liquid hydrogen, hydrazine, liquid ammonia, and either hydrazine hydrate or hydroxylamine. Three oxidants with a given fuel had the following order: liquid ozone, liquid oxygen, and 100-percent hydrogen peroxide."

Report presenting aerodynamic and icing investigations conducted in the icing research tunnel on a model of a turbojet-engine nacelle with a long straight air inlet in order to provide basic design criteria for hot-gas blowback systems. The most uniform temperature distribution was obtained with a bleedback of 4.4 percent at a gas temperature of 1000 degrees Fahrenheit and resulted in an average dry-air-temperature rise of 46 degrees Fahrenheit.

Report presenting the results of several investigations of the performance of different types of clamshell variable-area exhaust nozzle far turbojet engines to determine the efficiency of that type of exhaust nozzle as compared with conventional fixed-area conical exhaust nozzles. The investigations were conducted at zero-ram sea level conditions on three different full-scale turbojet engines and using five different nozzles.

"Abrupt, rudder-fixed aileron rolls have been made with the Douglas D-558-I airplane (BuAero No. 37972) at Mach numbers between 0.6 and 0.89. Rolls were made at aileron deflections between one-eighth and one-half the maximum available deflection. The results obtained indicate that the aileron effectiveness is independent of Mach number and deflection within the range investigated" (p. 1).

Report presenting an investigation in the 4- by 4-foot supersonic pressure tunnel at a Mach number of 1.41 to determine the static stability and control and drag characteristics of a model of a 35 degree swept-wing airplane. The effects of alternate fuselage shapes, wing camber, wing fences, and fuselage dive brakes on aerodynamic characteristics were also investigated.

Results are presented of wind-tunnel investigations at Mach numbers of 0.60 to 0.94 and angles of attack of -2 degrees to about 24 degrees to determine the lateral control characteristics of spoilers with various wing chord-wise and spanwise locations and spoiler spans and deflections on thin 60 degree delta wing of NACA 65a003 airfoil section parallel to free stream.

Memorandum presenting rolling stability derivatives for a complete model with a low-aspect-ratio wing and tail surfaces for a Mach number range of 0.70 to 0.94 and for an angle-of-attack range from 0 to 13 degrees for the lower Mach numbers. The model test results indicated regions of neutral or unstable damping in roll at Mach numbers of 0.85 and 0.90 in the higher angle-of-attack range for the basic model. Results regarding damping in roll, yawing moment and lateral force due to rolling, and aileron characteristics are provided.

Report presenting the lateral stability and control characteristics were investigated on the Convair XF-92A delta-wing airplane during the flights of the NACA research program. The investigation included sideslips, aileron rolls, and rudder pulses at a range of altitudes and indicated speeds. The lateral handling characteristics appear satisfactory when viewed in terms of gradually increasing sideslips, lateral control effectiveness, and period, and damping.

This report summarizes results on surveys taken by the U.S. Geological Survey made to determine the seismic velocity, electrical resistivity, and preliminary geology of rock in the U12n.03 tunnel, Nevada Test Site.

From abstract: High velocity disturbances are observed to propagate along the walls of a high explosive operated shock tube in advance of the plane shock. Experiments are presented which determine the dependence of the geometry, energy, and velocity of the disturbance on such variables as the gas contained in the shock tube, the shock strength, and the roughness and composition of the supporting boundary. A model is constructed to explain the flow within the disturbance. Arguments are presented which show the disturbance to result from radiation originating in the luminous plane shock...The purpose of this paper is to present the results of initial investigations made in an effort to describe the phenomenon of strong shocks developed in a shock tube by the detonation of high explosive charge.

Abstract: The rate of reaction of oxygen with arc-melted and rolled iodide thorium has been found to obey the parabolic rate law in the temperature range of 850 to 1415 C at 1 atmosphere pressure. The rate constant can be expressed as k = 6 x 10⁷ x e⁻⁶³³⁰⁰/RT cm²/sec. The energy of activation, 63,300 cal/mole, has a probable error of 2,100 cal/mole.

This report describes progress in testing the corrosion resistance of alloys of TCl₄. The steps and conditions of the testing procedures are given as well as conclusions and photos of TCl₄.

Abstract: "An investigation of the mercury salvage program has resulted in the development of an improved high compacity type of distillation apparatus. The still, electrically heated and essentially automatic in its operation, will produce at a rate greater than 75 pounds per hour and develop a product 99.99% pure or better. This still will handle the lowest grade crude of amalgam that can pass through the feed lines and will continue to develop a pure prodcut for comparatively long periods of time. The clean-out operation is amazingly simple and convenient and may be done within one-half hour while the apparatus itself is still hot. Two models of this design are scheduled for installation in a mercury recovery room of the Alpha Analytical Department of Building No. 9207."

Experiments with a simple pulsed magnetic field in cusped geometry are described. The plasma is generated inside the containment region rather than injected from an external source. It was found that creation of the plasma by a linear pinch discharge is most successful. Only qualitative studies have been carried out so far, using time-resolved visual observation of the plasma. Well-defined plasma bodies located in the central region between the cells were photographed. In order to make them clearly visible, a few percent of argon was added to the hydrogen.

General overview of the metric system.